Using a custom field value to set due date with Automation for jira

[Avinash]

Hi,

I am trying to use a custom field value like estimate (number field) and set the due date based on the field. How can I achieve this? 

Example custom field value is 2, created date is 02/12/2020, I would like to set due date to 02/14/2020 

[Avinash · Accepted solution]

I figured it

{{#now}}func=plusDays({{issue.CustomField_11111}}){{/}}

[andrewclam]

How might one find the custom field's id?